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Bremer Financial Corporation <br />Project B2008939 <br />November 17, 2020 <br />Page 20 <br /> <br /> <br /> <br />Table 8. Recommended Bituminous Pavement Sections <br />Use Light Duty Heavy Duty <br />Light Duty with <br />Sand Subbase <br />Heavy Duty with <br />Sand Subbase <br />Minimum asphalt thickness <br />(inches) 3 1/2 4 1/2 3 1/2 4 <br />Minimum aggregate base thickness <br />(inches) 8 10 6 8 <br />Minimum granular subbase <br />(inches) --- --- 18 18 <br /> <br /> <br />C.7.b. Bituminous Pavement Materials <br />Appropriate mix designs are critical to the performance of flexible pavements. We can provide <br />recommendations for pavement material selection during final pavement design. <br /> <br />C.7.c. Subgrade Drainage <br />We recommend installing perforated drainpipes throughout pavement areas at low points, around catch <br />basins, and behind curb in landscaped areas. We also recommend installing drainpipes along pavement <br />and exterior slab edges where exterior grades promote drainage toward those edge areas. The <br />contractor should place drainpipes in small trenches, extended at least 8 inches below the granular <br />subbase layer, or below the aggregate base material where no subbase is present. <br /> <br />C.7.d. Performance and Maintenance <br />We based the above pavement designs on a 20-year performance life for bituminous. This is the amount <br />of time before we anticipate the pavement will require reconstruction. This performance life assumes <br />routine maintenance, such as seal coating and crack sealing. The actual pavement life will vary depending <br />on variations in weather, traffic conditions and maintenance. <br /> <br />It is common to place the non-wear course of bituminous and then delay placement of wear course. For <br />this situation, we recommend evaluating if the reduced pavement section will have sufficient structure to <br />support construction traffic. <br /> <br />Many conditions affect the overall performance of the exterior slabs and pavements. Some of these <br />conditions include the environment, loading conditions and the level of ongoing maintenance. With <br />regard to bituminous pavements in particular, it is common to have thermal cracking develop within the <br />first few years of placement, and continue throughout the life of the pavement. We recommend